Click the appropriate position to mark the end point of the line.
The values of taps that fall between the start and end points are aligned along the line.
To adjust the stereo balance in stereo input/stereo output configurations: Drag the Pan parameter—which appears as a dot on the tap—up or down the tap to adjust the stereo balance.
By default, stereo spread is set to 100%. To adjust the spread width, drag either side of the dot. As you do so, the width of the line extending outward from the dot changes. Keep an eye on the Spread parameter in the Tap parameter bar while you are adjusting.
Logic Pro Instruments: PDF